Teleutospores. a7 
vested with a thick membrane (Plate III. Figs. 18, 19). 
Their subsequent development is similar to that which 
occurs in the uredospores. The investing membrane, 
however, undergoes considerable thickening, and becomes 
darker in colour. At the apex of the spore this thicken- 
ing is most marked, but it does not always follow that 
here the depth of its colour is most noticeable, although 
it generally is so. This is, to a certain extent at any 
rate, owing to the fact that the apex of the spore is per- 
forated by a small tubular canal, which is, however, by 
no means easy to observe in the perfect spore, but whose 
presence is obvious enough in those spores which have 
already germinated, or are in the act of germinating. 
The interior of this membrane is lined by a very thin 
endospore. This can be brought into view by the action 
of undiluted sulphuric (H,SO,) or nitric acid (HNO,). 
These reagents exert no influence on the investing mem- 
brane, but cause the endospore to shrink away from it. 
The endospore encloses a finely granulated protoplasmic 
mass, near the middle of which is usually a vacuole. The 
teleutospore remains for alonger or shorter period attached 
to the spore-bed by the lower part of its spore-forming 
hypha, which contains a hyaline or watery material, and 
constitutes a stem (pedicel, peduncle) to the teleutospore. 
Teleutospores may be simple (Uromyces, Melampsora) 
or compound (Puccinia, Triphragmium, Chrysomyxa). 
The teleutospores of Uromyces are developed in the 
manner above described. The germinal canal is always 
at the apex of the spore. The membrane is generally 
smooth, but in some species, as Ur. alchemilla, it is 
studded with prominent wart-like tubercles, Similar 
tubercles are observed on some of the species affecting 
the Leguminose, but instead of remaining as discrete 
tubercles they become in part or wholly confluent, so as 
